Which of the following statements is always true?
a. workers being paid on commission make less money than if they are salaried.
b. workers being paid on commission get paid based solely on their performance.
c. workers being paid on commission are stressed over the amount of earnings they will have.
d. workers being paid on commission increase the accounting costs of the employer.

The statement that is always true is the b. Workers being paid on commission get paid based solely on their performance. That is because the pay on commission is proportional to the results: the more you sell the more you earn. So, the earnings are reflection of the results that the employee reaches, i.e. his/her performance. Take into account that option c. "workers being paid on commission are stressed over the amount of earnings they will have" is true only some times, because if the employee has a comfortable finance postion he/she will not necessarily be under stress.